Irinotecan belongs to the group of cancer-fighting medications known as antineoplastics. It kills cancer cells by interfering with the genetic material DNA, which is necessary for their growth and reproduction. Irinotecan is usually used in combination with other medications to treat colon or rectal cancer. It may also be used alone to treat colon or rectal cancer that has spread to other areas of the body after receiving treatment with 5-fluouracil.

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.

The recommended dose and dosing schedule of irinotecan varies according to the stage of therapy, the stage of cancer, the response to therapy, and the person's body size. Irinotecan is given in cycles that include rest periods between treatments. It is injected into a vein through a specially prepared site on the skin. The appropriate dose of irinotecan is usually given by an infusion over a period of about 90 minutes.  This cycle is repeated until it is determined that treatment is completed. Very careful handling of this medication is required. Irinotecan is always used under the supervision of a doctor in a hospital or similar setting with access to sterile equipment for preparation.

Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, discuss any concerns you may have with your doctor.

It is important this medication be given exactly as prescribed by your doctor. If you miss an appointment to receive irinotecan, contact your doctor as soon as possible to reschedule your appointment.

Each mL of sterile, clear, light yellow, aqueous solution contains 20 mg irinotecan hydrochloride trihydrate. Nonmedicinal ingredients: sorbitol, lactic acid, and water for injection. Sodium hydroxide and/or hydrochloric acid may be used to adjust the pH to 3.0 to 3.8.

Do not use this medication if you:

• are allergic to irinotecan or any ingredients of this medication
• are taking an azole antifungal (e.g., fluconazole, ketoconazole, itraconazole)
• have hereditary fructose intolerance
• have taken ketoconazole within the past week

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• decrease in or loss of appetite
• increased saliva production
• increased sweating
• indigestion
• nausea and vomiting
• pain at injection site
• stomach cramps or pain
• temporary hair loss
• weakness

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• flushing
• signs of anemia (low red blood cells; e.g., dizziness, pale skin, unusual tiredness or weakness, shortness of breath)
• signs of clotting problems (e.g., unusual nosebleeds, bruising, blood in urine, coughing blood, bleeding gums, cuts that don't stop bleeding)
• skin rash
• sores, ulcers, or white spots on lips or in mouth
• symptoms of high blood sugar (e.g., frequent urination, increased thirst, excessive eating, unexplained weight loss, poor wound healing, infections, fruity breath odour)
• symptoms of ileus (decreased passage of material through the digestive system; e.g., abdominal swelling, feeling "full", constipation, loss of appetite, nausea vomiting)
• tightness in chest
• unusual and severe tiredness or weakness
• vision changes
• vomiting for more than 12 hours
• watery eyes

Seek immediate medical attention if any of the following occur:

• diarrhea, with or without stomach cramps or sweating
• diarrhea with fever or that lasts longer than 24 hours
• dizziness or lightheadedness
• fainting
• pain or burning during the injection
• runny or stuffy nose
• shortness of breath or troubled breathing
• signs of bleeding in the stomach (e.g., bloody, black, or tarry stools; spitting up blood; vomiting blood or material that looks like coffee grounds)
• signs of a blood clot in the arm or leg (tenderness, pain, swelling, warmth, or redness in the arm or leg) or lungs (difficulty breathing, sharp chest pain that is worse when breathing in, coughing, coughing up blood, sweating, or passing out)
• signs of dehydration (e.g., decreased urine, dry skin, dry and sticky mouth, sleepiness, dizziness, headache, thirst, confusion)
• signs of a heart attack (e.g., chest pain or pressure, pain extending through shoulder and arm, nausea and vomiting, sweating)
• signs of infection (symptoms may include fever or chills, severe diarrhea, shortness of breath, prolonged dizziness, headache, stiff neck, weight loss, or listlessness)
• signs of a serious allergic reaction (e.g., abdominal cramps, difficulty breathing, nausea and vomiting, or swelling of the face and throat)
• signs of stroke (e.g., sudden or severe headache; sudden loss of coordination; vision changes; sudden slurring of speech; or unexplained weakness, numbness, or pain in arm or leg)
• slurred speech or difficulty speaking

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Anemia: This medication may cause low levels of red blood cells. If you experience symptoms of reduced red blood cell count (anemia) such as shortness of breath, feeling unusually tired, or pale skin, contact your doctor as soon as possible.

Your doctor will do blood tests regularly to monitor the number of specific types of blood cells, including red blood cells, in your blood.

Bleeding: Irinotecan may cause a reduced number of platelets in the blood, which can make it difficult to stop cuts from bleeding. If you notice any signs of bleeding, such as frequent nosebleeds, unexplained bruising, or black and tarry stools, notify your doctor as soon as possible. Your doctor will order routine blood tests to make sure potential problems are caught early.

Blood clots: This medication may increase the chance of blood clot formation, causing reduction of blood flow to organs or the extremities.

If you experience symptoms such as sharp pain and swelling in the leg, difficulty breathing, chest pain, blurred vision, or difficulty speaking, contact your doctor immediately.

Diabetes: This medication may cause an increase in blood glucose levels. If you have diabetes, your doctor should closely monitor your condition while you are taking irinotecan. Discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Diarrhea: Diarrhea occurring more than 24 hours after treatment is a common side effect. Your doctor may recommend that you take oral (by mouth) loperamide if diarrhea occurs. It is important that diarrhea be treated promptly and aggressively if it occurs. If you are taking loperamide as directed by your doctor and diarrhea continues for more than 48 hours, get medical attention immediately. It is also important that you drink plenty of fluids if diarrhea occurs.

Drowsiness/reduced alertness: Irinotecan can cause fatigue, dizziness or vision changes. Avoid activities such as driving or operating machinery if the medication affects you in this way.

Infection: As well as killing cancer cells, this medication can reduce the number of cells that fight infection in the body (white blood cells). If possible, avoid contact with people with contagious infections. Tell your doctor if you begin to notice signs of an infection, such as fever or chills, severe diarrhea, shortness of breath, prolonged dizziness, headache, stiff neck, weight loss, or listlessness. Your doctor will do blood tests regularly to monitor the number of specific types of blood cells in your blood.

Bowel obstruction and inflammation: There have been reports of inflammation of the digestive system after being treated with irinotecan. This can cause the passage of material through the intestines to slow down or stop. Bowel obstruction can become a severe medical condition. If you experience symptoms of this condition, such as abdominal cramping, loss of appetite, feeling full, constipation, abdominal swelling, nausea or vomiting with these symptoms, contact your doctor as soon as possible.

Lung inflammation: Rarely, lung inflammation (interstitial lung disease), causing difficulty breathing has occurred in some people taking this medication. This complication can be serious and sometimes fatal. If you experience new or worsening shortness of breath or cough (with or without fever) at any time while you are being treated with irinotecan, contact your doctor immediately.

Vaccines: Live vaccines should not be given while you are being treated with irinotecan. Any required vaccinations should be completed before starting cancer treatment or postponed until treatment is complete.

Pregnancy: Irinotecan may cause birth defects if either parent is using irinotecan at the time of conception, or if it is taken during pregnancy. Both partners should use a reliable form of birth control while taking this medication. If you become pregnant while using irinotecan, contact your doctor immediately.

Breast-feeding: It is not known if irinotecan passes into breast milk. People should not breast-feed while using irinotecan due to the risk of harm to the infant.

Children: The safety and effectiveness of using this medication have not been established for children.

Seniors: There is an increased risk of diarrhea for people over the age of 65. Discuss any concerns you may have with your doctor.

For a full list of interactions, use the Drug Interaction Checker available on the Drugs.com website.

If you are taking other medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.